The present invention relates to an assembly of a one-way clutch and a bearing which is to be attached to a stator of a torque converter, and more particularly to an assembly of a one-way clutch and a bearing in which a thrust bearing (needle bearing), a thrust washer, and the like are not used, and wear of sliding faces of a stator and a bearing support can be reduced.
A torque converter which is used as an automatic transmission of an automobile is configured so that, as shown in FIG. 9, a pump impeller 2 is rotated by an output shaft 1 of an engine, a turbine runner 4 is rotated by using ATF (Automatic Transmission Fluid), the rotational torque of the turbine runner 4 is increased via a stator 3, and the power is then transmitted to an input shaft 5 of the transmission. A one-way clutch 6 is attached to the stator 3. An inner race 6b of the one-way clutch 6 is non-rotatably placed by spline fitting or the like on a stationary shaft 11 which is placed around the input shaft 5. Depending on the vane angle of the stator a thrust load is applied to the one-way clutch 6. In order to absorb the load, therefore, thrust bearings 12 and 13 (or thrust washers) are usually placed on both the sides of the one-way clutch 6, respectively.
When the thrust bearings 12 and 13 (or thrust washers) are placed on both the sides of the one-way clutch 6, however, the number of parts is increased, the configuration is complicated, and it is disadvantageous from the view point of space. Consequently, the assignee of the present application has proposed an assembly of a one-way clutch and a bearing in which, as shown in FIG. 6, such a thrust bearing 12 and the like are not used, small gaps 21 and 20 are respectively formed between a flange portion 3b, that elongates radially inward from a boss portion 3a of the stator 3, and a pump-side member 2a. A bearing support 7 and a turbine-side member 4a are placed on the opposite side, and dynamic pressure grooves are formed in sliding faces of the flange portion 3b of the stator 3 and the bearing support 7 (Japanese Patent Publication (Kokai) No. HE18-247251).
As shown in FIGS. 7(A) and 7(B), for example, herringbone-like or V-like dynamic pressure grooves 10, 10, . . . are formed in the surface of the side face of the flange portion 3b of the stator 3, or, as shown in FIGS. 8(A) and 8(B), herringbone-like or V-like dynamic pressure grooves 9, 9, . . . are formed in the surface of the side face of the bearing support 7. A dynamic pressure is generated by relative rotation of the stator 3 and the like, so that the thrust load is supported and thrust bearings or thrust washers are not required.
The stator 3 and the bearing support 7, in which the herringbone-like or V-like dynamic pressure grooves 10 or 9 are formed in the sliding face, are produced from a synthetic resin. The ATF (Automatic Transmission Fluid) which generates a dynamic pressure is sucked into the dynamic pressure grooves 10 (9) from the inner and outer radial sides of the side faces of the stator 3 and the bearing support 7 to join together in the apexes of the dynamic pressure grooves 10 (9), i.e., in the center of the sliding faces, with the result that the pressure is raised to exert the dynamic pressure effect. In such pressure rise, however, the pressure is generated at the junctions of the dynamic pressure grooves 10 (9), but the high-pressure fluid has no way of escape, and hence the fluid temperature is abruptly raised in accordance with the sliding operation of the side faces of the stator 3 and the bearing support 7. As a result, there arises a problem in that the sliding faces are easily worn.
The invention has been conducted in view of the above-discussed problem. It is an object of the invention to provide an assembly of a one-way clutch and a bearing in which a thrust load due to a stator can be absorbed, a dynamic pressure can be generated, and, even when the pressure becomes high, the temperature is prevented from being abruptly raised, so that wear and the like of sliding faces can be prevented from occurring.
In order to solve the problem, the present invention provides an assembly of a one-way clutch and a bearing in which a bearing is placed between a one-way clutch attached to a stator of a torque converter, and a pump member adjacent to a flange portion formed on the stator, and a turbine member adjacent to a bearing support which is placed on a side opposite to the flange portion of the stator, and
dynamic pressure grooves (3c) and an escape groove(s) (3d) serving as the bearings are formed in at least one of opposing faces of the flange portion formed on the stator and the pump member, or opposing faces of the bearing support which is placed on the side opposite to the flange portion of the stator, and the turbine member.
Furthermore, the present invention provides that the escape groove(s) is a ring-like groove (3e) which is formed in a circumferential direction of a face, the dynamic pressure grooves being formed in the face.
Moreover, the present invention also provides that the escape grooves are grooves (3f) which are radially formed at predetermined angular intervals in a circumferential direction of a face, the dynamic pressure grooves being formed in the face whereat the dynamic pressure grooves are not formed.
Furthermore, the present invention additionally provides that a bearing support is placed in place of the flange portion of the stator.
Moreover, the present invention provides that the bearing support is used as the flange portion of the stator, and the flange portion of the stator is used as the bearing support.